Addressing spina bifida in-utero

Fetal Concerns Center team breaks ground with prenatal surgery that improves infants’ outcomes

Neural tube defects are the most common congenital central nervous system anomaly, with between 70,000 and 100,000 people in the U.S. affected. The most common type, spina bifida, affects an estimated 1,500 babies a year.

Spina bifida occurs when the neural tube fails to close within the first four weeks of pregnancy. The severity ranges from spina bifida occulta, a mild form in which the spinal cord and the surrounding structures remain inside the baby but the back bones in the lower back area fail to form normally, to myelomeningocele (MMC), the most severe form in which the spinal cord and nerves develop outside the fetus and are contained in a fluid-filled sac visible on the outer back.

Most of these children will have weakness and loss of sensation below the defect, problems with bowel and bladder function, and hydrocephalus, a buildup of cerebrospinal fluid in the brain. Most also require a ventriculo-peritoneal shunt to divert cerebrospinal fluid to treat the associated hydrocephalus, itself a risk factor for complications such as infection, obstruction and shunt revision surgery.

Until recently, such infants were treated postnatally. But the ability to diagnose MMC early in pregnancy via blood tests, ultrasound and MRI led to the development of prenatal surgical intervention, which can reduce the need for a postnatal shunt, improve lower body function and reverse hindbrain herniation, long-term studies find.¹

In 2014, after nearly two years of preparation, the Fetal Concerns Center at the Children’s Wisconsin in Milwaukee performed the state’s first prenatal spina bifida repair, becoming one of fewer than 20 centers around the country to offer the procedure. The team now performs several a year.

The process begins with an intensive evaluation of the mother and fetus to see if they are good candidates, explains Andrew B. Foy, MD, a neurosurgeon at the Fetal Concerns Center. “The baby needs to be otherwise healthy with no other anatomic defects,” he says. The spinal defect must also be within a certain range within the spine. In addition, the mother’s weight and history of previous premature births play a role.

The Fetal Concerns Center takes a comprehensive, multidisciplinary approach to treating spina bifida, Dr. Foy says. An advanced practice nurse, Eileen C. Sherburne, APNP, manages the spina bifida clinic and serves as an educator, case manager, advocate and consultant for families before and after birth. She provides prenatal counseling for families who know their baby will be born with spina bifida and assists with care management when patients have a procedure or receive care at the hospital.

The surgery itself takes about two hours and requires a team of more than 20 medical professionals. “The last surgery we did we had 28 people in the operating room, all of whom belonged there,” Dr. Foy says. They included circulating and scrub nurses; echocardiogram and ultrasound technicians; and clinicians from transfusion medicine, pharmacy, pediatrics, obstetrical anesthesia, fetal cardiology, maternal fetal medicine, pediatric surgery and neurosurgery.

The challenges of the surgery require extensive preparation. “We frequently do a dress rehearsal in the operating room the day before so everyone is on the same page,” he says. They also go through a three-page checklist for every case.

After surgery, the mother remains hospitalized for about five days to monitor for contractions, followed by frequent - usually weekly - postoperative assessments.

Nonetheless, Dr. Foy says, “the majority of babies end up being born prematurely between 30 and 37 weeks, so there is certainly a risk of premature birth.” There is also a 5 percent risk of fetal death from the procedure, as well as risks of blood loss, pulmonary edema and long-term reproductive health issues for the mother, including uterine rupture. There is limited data on the effects on future pregnancies, although the few published reports available suggest a higher risk of uterine rupture and dehiscence.^2,3

Given the relatively high risk of fetal death and other complications, why do eligible moms choose the surgery over postpartum repair? “What largely drives them is that many of the complications from spina bifida come from hydrocephalus,” Dr. Foy says. “The surgery cuts the risk of needing a shunt in half, from 80 to 40 percent, which can lead to an improvement in the child’s quality of life.” Even if the infant does develop hydrocephalus and needs a shunt, it is usually several months after birth, versus days in infants who did not receive prenatal surgery. In selected cases, some of these children have been able to avoid a shunt with an endoscopic procedure that is more likely to be successful in older infants.